Balancing mechanism for fluid translating device

ABSTRACT

A fluid translating device having a rotor rotatably mounted within a bore in a camblock that is supported within a housing. The rotor is spaced from the bore to define an annular space and has plates extending from opposite ends thereof with the end portions of the side plates being in overlapping spaced relationship with the opposed surfaces of the camblock. The opposed surfaces of the camblock have a plurality of circumferentially spaced recesses formed therein with each of the recesses communicating with the annular space through a slot. Thus, fluid being translated between inlet and outlet ports flows in the spaces between the end portions of the plate and the adjacent surfaces of the camblock and seals the annular space, while some of the pressure fluid is received in the respective recesses to maintain the camblock in a centered position between the respective end portions of the plates. In one embodiment, the recesses are arcuate and located on a common diameter greater than the diameter of the bore. In an alternate embodiment, the recesses are arcuate and one end of each recess is closer to the surface of the bore than the opposite end while the camblock has cutout portions extending from the bore surface and from the outer surface, so that all portions of the plate end portions are exposed to the fluid. In a further embodiment, the recesses are substantially longitudinal and extend chordally of the center of the bore. The camblock also has surfaces adjacent the housing opening which are beveled from a center point to produce substantial line contact between the housing opening and the camblock.

United States Patent J ansson [54] BALANCING MECHANISM FOR FLUIDTRANSLATING DEVICE [72] Inventor: Birger F. Jansson, Racine, Wis. [73]Assignee: J. I. Case Company [22] Filed: April 13, 1970 [21] Appl. No.:27,733

[52] US. Cl. ..418/75, 418/107, 418/133, 277/96 [51] Int. Cl ..F0lc21/00, F03c 3/00, F04c 27/00 [58] Field of Search ..418/75, 76, 77, 78,79, 80, 418/81, 82,133, 31, 107, 108; 277/96;

Primary Examiner-Carlton R. Croyle Assistant Examiner-John J. VrablikAttorney-Dressler, Goldsmith, Clement & Gordon [57] ABSTRACT A fluidtranslating device having a rotor rotatably [4 1 Oct. 3, 1972 mountedwithin a bore in a carnblock that is supported within a housing. Therotor is spaced from the bore to define an annular space and has platesextending from opposite ends thereof with the end portions of the sideplates being in overlapping spaced relationship with the opposedsurfaces of the carnblock. The opposed surfaces of the carnblock have aplurality of circumferentially spaced recesses formed therein with eachof the recesses communicating with the annular space through a slot.Thus, fluid being translated between inlet and outlet ports flows in thespaces between the end portions of the plate and the adjacent surfacesof the carnblock and seals the annular space, while some of the pressurefluid is received in the respective recesses to maintain the carnblockin a centered position between the respective endportions of the plates.

In one embodiment, the recesses are arcuate and located on a commondiameter greater than the diameter of the bore. In an alternateembodiment, the recesses are arcuate and one end of each recess iscloser to the surface of the bore than the opposite end while thecarnblock has cutout portions extending from the bore surface and fromthe outer surface, so that all portions of the plate end portions areexposed to the fluid. In a further embodiment, the recesses aresubstantially longitudinal and extend chordally of the center of thebore.

The carnblock also has surfaces ad acent the housing opening which arebeveled from a center point to produce substantial line contact betweenthe housing opening and the carnblock.

14 Claims, 13 Drawing Figures PATENTEDUBT 3 m2 59g )Bzrger f l/fr SHEET1 OF 2 1155022 GHQ 5 BALANCING MECHANISM FOR FLUID TRANSLATING DEVICEBACKGROUND OF THE INVENTION The present invention relates generally tofluid devices and, more particularly, to a balancing mechanism forrelatively movable parts of the fluid device.

Fluid translating devices of the type commonly referred to as vane-typepumps are well known in the art, as exemplified by [1.8. Pat. No.3,187,676. Generally these fluid translating devices include a housinghaving an opening therein which slidably receives and supports acamblock. The camblock is generally supported for vertical movementwithin the housing to vary the output, as well as the direction of flowof fluid through the pump.

The camblock has an internal bore with a rotor rotatable about a fixedaxis in the bore. The rotor has a plurality of radially extending slots,each of which slidably supports a vane having a free end held inengagement with the internal surface of the camblock bore by suitablebiasing means. The camblock and rotor cooperate to define an annularspace which is in communication onopposite sides thereof with inlet andoutlet ports formed in the housing.

In order to enclose the opposite ends of the annular space between thecamblock and the rotor, the rotor normally has a pair of circular platessecured to opposite ends thereof with the end portions of the platesbeing in overlapping relationship with an adjacent portion of thecamblock.

Thus, rotation of the rotor within the bore or workin g chamber willcause the vanes to translate fluid from the inlet port to the outletport across the annular space or zone defined between the camblock andthe rotor. The particular spacing between the camblock and the rotor andthe eccentricity of the bore axis and the rotor axis will cause thepressure of the fluid to be increased as the fluid is translated fromthe inlet to the outlet port.

In fluid pumps of this type, difficulties have been encountered inmaintaining an effective fluid seal between the plates rotating onopposite sides of the fixed camblock while still eliminatingmetal-to-metal contact between the adjacent surfaces of thecamblock andthe side plates. Heretofore, it was considered necessary to machine theadjacent surfaces of the camblock and the side plates, as well as theopposite ends of the rotor, to very close tolerances in order to preventmetal-to-metal contact between the adjacent surfaces. While themachining to very close tolerances may be accomplished at considerableexpense, there is still another difficulty in that the spacing betweenthe two surfaces must be sufficient to allow free rotation of the rotorand plates. Furthermore, in a reversible pump,

the camblock must be readily movable in the housing.

Thus, it has been found that if the spacing is too small, it may resultin metal-to-metal contact between the adjacent surfaces and will alsoprevent adjustment of the camblock, within the pump housing. If thespacing between the "surfaces is too great, excessive leakage from theannular space will be encountered and there is a tendency for thecamblock to tilt relative to the side plates and result in a jamming ofthe camblock within the housing opening to prevent movement of thecamblock to accommodate any misalignment between the rotor and boreaxis. This again may result in metalto-metal contact.

In view of these difliculties, there still remains a need for a simpleand efiicient manner of sealing the ad jacent surfaces of the camblockand the plates and yet allowing sufficient clearance between the twosurfaces to accommodate misalignment of the parts during operation andadjustment of the camblock.

SUMMARY OF THE INVENTION The present invention contemplates a variablevolume fluid translating device which has one of the relatively movableelements floatingly supported with respect to the other of therelatively movable elements. The floating support for the one elementrelative to the other element is accomplished by forming recesses on thefixed element which are in communication through slots with the fluidtranslated through the device to maintain a predetermined spacingbetween adjacent surfaces of the respective elements.

Stated another way, the present invention contemplates a fluidtranslating device of the type having a housing supporting a camblockwithin an opening and having a rotor supported for rotation about afixed axis within a working chamber defined in the camblock. The annularzone between the. camblock and the rotor is sealed by a pair of platesforming part of the rotor and extending adjacent opposite surfaces ofthe camblock with the spacing between the plates being greater than theaxial length of the camblock, so as to produce small spaces or gapsbetween the adjacent surfaces of the camblock and the plates. Thecamblock surfaces have circumferentially spaced recesses formed thereinwhich are in communication with the annular zone or space through slotsdefined in the camblock surfaces.

With the above arrangement, pressured fluid within the annular zone isreceived into the recesses on opposite ends of the camblock and tends tomaintain the camblock in a centered position relative to the spacedplates. Furthermore, by utilizing the recesses and the substantiallyunrestricted flow into the recesses from the annular space, as thespacing between the adjacent surfaces of the camblock and the plate onone side is decreased and the opposite side is increased, the pressuredfluid received into the recesses, which is or has a pressuresubstantially equal to that of the pressured fluid within the annularzone, will at all times tend to maintain a true centered position of thecamblock relative to the spaced plates and prevent metal-to-metalcontact between the adjacent surfaces of the rotor assembly and thecamblock assembly.

In one embodiment of the present invention, the opposed surfaces of thecamblock have circumferentially spaced arcuate recesses which arelocated on a common diameter concentric with the center of the camblockbore. In an alternative embodiment, the camblockhas a ring portionadjacent the bore which has arcuate recesses with opposite ends of eachof the recesses being located on spaced diameters concentric with thebore. In this embodiment, the ring portion has circumferentially spacedcutouts or notches extending from the outer end inner perimeter of thering portion and located between each of the adjacent ends of therespective recesses, so that each radial portion of the adjacentrotating plate will be lubricated several times during each cycle ofrevolution. In a still further embodiment, the recesses extend chordallyof the bore and are defined in raised portions of the surface, so thatagain the entire adjacent rotating surfaces will be lubricated severaltimes during each cycle of revolutron.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF DRAWINGS FIG. 1 of thedrawings discloses a horizontal sectional view of a fluid translatingdevice having the present invention incorporated therein;

FIG. 2 is an end view of the camblock assembly forming part of the fluidtranslating device of FIG. 1;

FIG. 3 is an enlarged fragmentary view of the camblock and rotorassembly shown in FIG. 1;

FIG. 3a (appears with FIG. 4a) is a pressure-area diagram for the flowof fluid through the gap shown in FIG. 3;

FIG. 4 is a view similar to FIG. 3;

FIG. 4a is a pressure-area diagram for the flow of fluid through the gapshown in FIG. 4;

FIG. 5 is an end view of the cam ring portion of the camblock showing amodified form of the invention;

FIG. 5a is a sectional view taken generally along line Sa-Sa of FIG. 5;

FIG. 5b is a sectional view taken generally along line Sb-Sb of FIG. 5;

FIG. 50 is a sectional view taken generally along line 5c-5c of FIG. 5;

FIG. 6 is a view similar to FIG. 5 showing a further modified form ofthe camblock;

FIG. 6a is a sectional view taken along line 6a-6a of FIG. 6; and

FIG. 6b is a sectional view taken along line 6b-6b of FIG. 6.

DETAILED DESCRIPTION While this invention is susceptible of embodimentin many different forms, there is shown in the drawings and will hereinbe described in detail several specific embodiments, with theunderstanding that the present disclosure is to be considered anexemplification of the principles of the invention and is not intendedto limit the invention to the embodiments illustrated.

FIG. 1 of the drawings discloses a fluid translating device 10 of thetype generally referred to as a reversible flow, vane-type, variablevolume pump. The fluid translating device or pump 10 includes a housingassembly 12, a camblock assembly 14 and a rotor assembly 16. The housingassembly 12 takes the form of a pair of pieces 18 and 20 extending fromopposite ends of a centerpiece 22 and are interconnected by a pluralityof bolts 23. The pieces 18 and 20 cooperate with the centerpiece 22 todefine an opening or cavity 24 having a pair of ports 26 and 28 locatedon opposite sides thereof.

The opening 24 of the housing 12 receives and slidably supports thecamblock assembly 14 which includes a camblock 30 and a cam ring 32. Thecam ring 32 has a central bore 34 which is in communication at oppositesides of the respective ports 26 through passageways 36 and 38,respectively, extending through the camblock and the cam ring. While thecamblock assembly is shown as being formed of two pieces, it may readilybe formed in a single piece and will hereinafter be referred to as thecamblock with the ring being referred to as a ring portion.

The rotor assembly cooperates with the bore or working chamber 34defined in the camblock 14 to produce an annular space or zone 40 whichdefines a lap space for fluid from one of the ports, 26, 28, to theother of the ports, 26, 28. For this purpose, the rotor assembly 16includes a rotor 42 splined at 44 to a shaft 46, which is rotated aboutthe fixed axis within the housing on bearings 48 and 50 received inbores in the end pieces 18 and 20. The rotor 42 has a plurality ofcircumferentially radially extending slots 52, each of which receivesand slidably supports a vane 54, the outer end of which is in contactingengagement with the surface defined by the bore 34 by suitable biasingmeans not shown).

The rotor assembly 16 further includes a pair of plates 56 and 58,commonly referred to as side plates, that are supported for rotationwith the rotor 42 adjacent the opposite ends thereof by being splined tothe shaft 46. Each of the circular plates 56 and 58 has an end portionwhich is in overlapping juxtaposed relation to the adjacent surfaces ofthe cam ring 32. Thus, the adjacent surfaces 60 and 64 of the respectiveside plates 56 and 58, respectively, cooperate with the opposed surfaces62 and 66 of the ring portion 32 to substantially enclose the oppositeends of the annular space 40.

As was indicated above, the fluid translating device 10 is of thereversible and variable volume type, which is accomplished by having thecamblock assembly 14 vertically shiftable within the opening 24 torearrange the eccentric relationship between the axis of the bore 34 andthe axis of the shaft 46 to thereby reverse the direction of flow of thepump. Assuming that the axis of the bore 34 is below the axis of theshaft 46 and the shaft is rotated in a counterclockwise direction, fluidwill be translated from the port 28 to the port 26 and the pressure ofthe fluid will be increased as it is translated through the lap spacedefined by the annular space or zone 40 between the ports.

As was indicated above, in order to translate fluid between the ports 26and 28, it is necessary to produce relative rotation between theadjacent surfaces 60 through 66. To accommodate such relative rotationof the adjacent surfaces, it would be desirable to produce as muchspacing between the surfaces as possible to thus eliminate anymetal-to-metal contact to prevent wear on the adjacent surfaces. On theother hand, in order to maintain the efficiency of the pump at itshighest level, it is necessary that the spacing between the adjacentsurfaces of the plate and the ring portion be at a minimum to insurethat the fluid is all translated between the ports.

The problem becomes even more acute when the rotor assembly 16 isrotated very rapidly and the pressure of the fluid is increasedsubstantially between the inlet and the outlet ports. For example, whenthe fluid is received into the inlet port at an elevated pressure andthe pressure thereof is increased to approximately 2,000 psi, theoptimum spacing between the movable member and the fixed member becomesextremely critical. In such instances, it is necessary to insure thatthere is a spacing between the adjacent surfaces at all times and yetthe spacing should not be so great as to allow a large quantity of fluidto escape from the annular space.

According to the present invention, the optimum condition is achieved byhaving the axial length of the ring portion 32 of the camblock slightlyless than the axial spacing between the adjacent surfaces 60 and 64 ofthe plates 56 and 58 to allow a minimum amount of pressured fluid flowfrom the annular space or zone 40 into each of the gaps and maintain thegaps substantially equal. This will maintain the camblock centeredbetween the respective surfaces 60 and 64 and the spacing between theadjacent surfaces is at all times sufficient to prevent the shearing ofthe oil film between the respective surfaces, thereby avoiding anysubstantial temperature increases of the fluid or the metal.

The above is accomplished by forming a plurality of recesses at spacedlocations on one of the adjacent surfaces of the ring portion or theplates and placing each of these recesses in communication with theannular space 40 through slots defined in the associated surface.

Referring particularly to FIGS. 1 through 4, the first or outer memberdefined by the camblock is floatingly supported adjacent the rotorassembly 16 and the gap between the adjacent surfaces, for example,surfaces 64 and 66, remains substantially constant by forming aplurality of circumferentially spaced recesses 70 in the surface 66 witheach of the recesses being in individual communication with the annularspace or zone 40 through a slot 72. In the embodiment illustrated, inFIGS. 2, 3, and 4, the surface 66 has six such recesses or pockets 70which are equally spaced circum ferentially of the ring 32, with each ofthe recesses being arcuate. The arcuate recesses are formed on a commondiameter which is greater than the diameter of the bore 34.

The opposite surface 62 (not shown) of the ring portion 32 of thecamblock will also have recesses and slots of identical configurationand location, shown in FIG. 2. The recesses or pockets 70 are arrangedso that three of the pockets in each of the surfaces are adjacent eachof the two ports 36 and 38. With this arrangement, when fluid is beingtranslated between the two ports, the fluid in the low-pressure portwill be received in six pockets located on opposite ends of one-half ofthe ring portion of the camblock, while the high-pressure port will bein communication with the remaining six pockets on the other half of thering portion.

As was indicated above, in the'optimum condition, the gaps or flowpaths, generally designated by the reference numeral 74, in FIGS. 3 and4, are equal in volume so that opposite ends of the cam ring portion 32of the camblock are equally spaced from the respective adjacent surfaces60 and 64 of the side plates 56 and 58. In this condition, the limitedamount of flow will not only maintainthe camblock centered, but willalso produce a fluid seal for the annular zone or lap space 40. If, forsome reason, or other, this optimum or equlibrium, centered condition ofthe camblock is disturbed, the spacing between one end surface of thecamblock and the adjacent surface of the plate will become greater whilethe spacing between the rotor assembly and the opposite end of thecamblock will become smaller. If the spacing between the adjacentsurfaces is decreases sufficiently, the oil film or flow of fluidthrough the gap 74 will be interrupted because of the shearing forcesencountered by the film of fluid.

However, the above condition of interruption of fluid flow is eliminatedby producing the recesses in one of the adjacent surfaces and placingthe recesses in communication with the fluid being translated. With thisarrangement, the resistance to movement of the adjacent surfaces towardseach other is increased nonlinearly as the spacing is decreased.Furthermore, considering the opposite end of the camblock, as thespacing between the adjacent surfaces is increased, the force on thecamblock from the flow of fluid will be substantially decreased. Thisphenomenon will be more readily understood by considering FIGS. 3a and4a, which, respectively, show the pressure-area diagram across the gaps74 for the two conditions illustrated in FIGS. 3 and 4. FIG. 3a showsthat the initial pressure drop across the radial area A, between theinner surface of the bore 34 and the inner edge of the recess isapproximately one-half of the pressure in the annular space or workingchamber 40. However, the pressure drop across the radial area A definedbetween opposite edges of the recesses or pockets 70 will be veryminimum because pressured fluid is constantly being supplied through theslots 72. The remainder of the pressure drop will occur along the area Awhich is between the outer edge of the ring portion 32 and the outeredge of the recess 70.

Considering now FIG. 4a, which shows the pressure area diagram acrossthe reduced gap 74 of FIG. 4, it will be appreciated that the amount offlow through the gap 74 will be considerably less than through the gapshown in FIG. 3, while the amount of fluid received into the recesses 70will substantially be the same for both conditions. Stated another way,the ratio of fluid flow through the gap versus the flow of fluid intothe recesses decreases as the size of the gap decreases. Thus, thepressure drop across the area A will be small and the pressure dropacross the area A will also be very minimal resulting in a major portionof the pressure drop occuring in the area A From a comparison of FIGS.3a and 4a, it will be appreciated that the total forces produced on onesurface FIG. 4 condition) will be substantially greater than the totalforce produced on the second surface (FIG. 3 condition). The totalresultant force tending to center the camblock will, therefore, increasenon-linearly or at a greater than the decrease in the size of the gap orspace. Stated another way, when the clearance or gap 74' is large, asshown in FIG. 3a, the pressure drop across the areas A, and A will besubstantially equal with substantially no pressure drop occurring in thearea A When the clearance or gap 74 is very small, the flow resistancefrom the recesses or pockets 70 will be substantially increased and,combined with the significant fluid flow through the slots 72 into thepockets 70, will maintain the pressure of the fluid within the pocket 70at a level considerably more than one-half the pressure of the fluidwithin the annular space or zone 40. Thus, the pressure drop along thearea A;, is considerably greater than the pressure drop along the areaA,. With such an arrangement, it is virtually impossible to decrease thespacing or clearance between the adjacent surfaces of the rotor assemblyand the camblock assembly to a point where the fluid film will besheared and cause an overheating of the adjacent surfaces of metal.Furthermore, the operation of the fluid seal and self-centering deviceof this type will not be dependent upon having a substantial pressuredrop from the annular space 40 to the outer edge of the camblock 14,because the relative pressure increase on one side of the rotor at arate greater than the decrease of pressure at the opposite side. Thiswill be true, regardless of the level of pressure of the fluid in theannular space. This arrangement is of considerable importance inpreventing metal-tometal contact when the pump is in a neutral conditionand the pressure of the fluid in not increased as it is passing betweenthe respective ports.

By eliminating the metal-to-metal contact, or even having the spacingbetween the adjacent surfaces of the rotor assembly and the camblockassembly maintained above a predetermined minimum, the friction lossesin this area of the pump are substantially eliminated and the variousparts need not have the extremely close tolerances heretofore considerednecessary.

As wasindicated above, the camblock is generally capable of beingshifted vertically relative to the axis of the rotor assembly 16, so asto vary the output, as well as the direction of flow of fluid throughthe pump. Generally, this is accomplished by forming the opening 24 of arectangular configuration and having the opposed vertical outer walls orsurfaces of the camblock assembly 14 (the surfaces which extendperpendicular to the axis of the ports 26 and 28) in contactingengagement with the adjacent surfaces of the opening thereby eliminatingany possibility of movement of the camblock assembly 14 axially betweenthe inlet and outlet ports.

However, such an arrangement creates a problem in that any tendency forthe rotor to become misaligned relative to the axis of the bore 34 willhave a tendency for the camblock to likewise become misaligned by thisamount. Such a condition could readily cause the camblock to becomejammed within the opening 24 to thereby prevent the free movement of thecamblock between the side plates and also prevent vertical shifting ofthe camblock to adjust the flow through the pump. Such a condition couldagain cause metal-tometal contact between the adjacent surfaces of thecamblock assembly 14 and the rotor assembly 16 resulting in ultimatefailure of the pump.

However, according to another aspect of the present invention, thisproblem is eliminated by producing vertical line contact between theadjacent walls or surfaces of the camblock and the opening 24. This isaccomplished by producing a high point 100 on each of the surfaces 102of the camblock 14, which are located adjacent the respective ports 26and 28. The point contact 100 is obtained by producing a taper or bevelin opposite directions from the center of the camblock. Thus, bytapering or beveling the respective surfaces, a comparatively smallsurface or substantial line contact will be produced between thesurfaces 102 and the adjacent surfaces of the opening, which will bealong the lines 100. It will be appreciated that the beveling ortapering of the respective surfaces 102 is greatly exaggerated in FIG. 1and in actual practice the taper will be relatively small, for example,on the order of 0.015 inch per inch.

In order to prevent fluid from leaking through the small space producedbetween the adjacent walls of the opening in the housing and thecamblock assembly, the camblock assembly preferably has a groove formedtherein with an O-ring 112, or other suitable sealing means received inthe groove. It will be appreciated that the line contact between thehousing assembly 12 and the camblock 14 will eliminate the possibilityof having the camblock become jammed in the housing opening.

A slightly modified embodiment of the present invention is disclosed inFIG. 5. Since the only difference between the embodiment shown in FIG. 2and that shown in FIG. 5 is the arrangement of the recesses, likereference numerals have been applied and the suffix a has been added. Inthe embodiment illustrated in FIG. 5, the recesses 700 are again arcuatein configuration and each recess is formed to the same radius. However,in this embodiment, the recesses are tilted relative to the center ofthe bore 340 so as to laterally offset the centers of the respectiveequal radii from the center of the bore 34a. Such an arrangement willresult in having one edge of the recess 70a spaced a greater distancefrom the center of the bore 340 than the opposite end of each of therecesses. Also, in the embodiment illustrated in FIG. 5, the ring has aplurality of opposed cutouts or notches and 122, respectively, extendingfrom the outer edge and the inner edge of the surfaces 66a and 62a (notshown). The inner edges or bases of the outer cutouts or notches 120 arelocated on a common diameter with all of the outer edges of the recessesor pockets 70a, while the outer edges or bases of the inner cutouts ornotches 122 are located on a common diameter with the inner edges of theopposite end of the respective recesses or pockets 700. With such anarrangement, the entire radial or overlapping area of the end plates 56and 58, which is in juxtaposed relation to the surface 66a and theopposite surface 62a (not shown) of the ring portion of the camblockwill be exposed to fluid several times during each cycle of rotation ofthe plates relative to the cam ring. This will insure a properlubrication of the side plates and will prevent any possibility ofthermal expansion due to lack of lubrication of the rotating surface.

A further modified embodiment of the invention is shown in FIG. 6 inwhich the surface 66b (as well as the opposite surface of the cam ringportion, not shown) has a polygonal or hexagonal raised portion witheach of the sides of the polygon having a linear recess 70b and each ofthe recesses or pockets 70b communicating through slots 7212 with theannular area or zone defined between the camblock and the rotorassembly. It will be appreciated that, in the alternative embodimentshown in FIG. 6, each area of the adjacent rotating side plate will beexposed to fluid for purposes of lubrication several times during eachcycle of rotation. This will necessarily result, because the chordalarrangement of the recesses or pockets 70b will have correspondingsegments of each of the pockets located at a different diameter than anadjacent segment. Furthermore, the substantially planar sides of thepolygonal raised portion 130 will produce inner and outer cutoutportions at circumferentially spaced locations on op- 9 posite sides ofthe raised portion 130. Of course, the upper surface of the raisedportion .130 will be the surface which is in juxtaposed relationship tothe adjacent surfaces of the plates 56 and 58.

The major advantage of sealing the areas between the rotor assembly andthecamblock assembly in the manner described above is that thehydrostatic effect of the seal will not be affected by changes in speedof rotation of the rotor assembly relative to the camblock assembly.Furthermore, the present invention allows for the manufacture of pumpsat a reduced cost, because the tolerances of the various parts can beincreased considerably.

While the fluid seal arrangement of the present invention has beendescribed in connection with a fluid translating device or pump, it isreadily apparent that the principle of the present invention could beincorporated to other fluid devices. For example, the selfcentering andsealing feature has particular utility in other hydraulic components,such as hydraulic cylinders, axially sliding valve spools, rotatingvalve spools, and components where a combined rotating and slidingmovement is required. For example, a valve spool could readily beself-centered and sealed within a valve bore by placingcircumferentially spaced recesses in either the valve spool or the boreand placing these recesses in communication with high-pressure fluidsupplied to the valve.

What is claimed is:

1. A fluid translating device comprising a housing having a rectangularopening therein; an inner member and an outer member cooperating toproduce an annular space with said members being relatively rotatable,said outer member having a rectangular peripheral surface cooperatingwith said opening, one of said members including portions havingsurfaces in overlapping spaced relation to adjacent surfaces of theother of said members to substantially enclose said annular space; meansdefining circumferentially spaced recesses in the surfaces of one ofsaid members, said recesses being in individual communication withsaidannular space, at spaced locations so that pressured fluid in saidannular space will be received in said recesses to maintain said othermember centered between said portions and flow of fluid between saidsurfaces will produce a fluidseal for said annular space; and meansdefining line contact along opposed portions of said peripheral surfaceand said opening, said line contact being centrally spaced and parallelto said surfaces of said outer member.

2. A fluid translating device as defined in claim 1, in which saidrecesses are arcuate and equally spaced about said annular space.

3. A fluid translating device as defined in claim 1, in which saidrecesses are chordally arranged and equally spaced about said annularspace.

4. A fluid translating device comprising a housing having an openingtherein and opposed inlet and outlet ports communicating with saidopening, a camblock supported for movement in said opening and having abore; a rotor rotatable about a fixed axis in said bore and cooperatingwith said bore to define an annular space; a pair of plates rotatablewith said rotor, said plates having end portions in overlapping relationwith respective opposed surfaces of said camblock with said camblockhaving an axial length between said surfaces which is less than thespacing between said plates to produce limited flow paths from saidannular space betweenisaid end portions and the adjacent surfaces ofsaid camblock; and means for producing circumferentially spacedelongated recesses and slots in said camblock surfaces, said recessesbeing spaced from said bore and said slots placing each of saidrecessesin communication with said annular space, whereby fluid translatedbetween said ports will be received in said recesses and maintain saidsurfaces spaced from said end portions and the fluid in said flow pathswill seal the annular space from the opening in the housing.

5. A fluid translating device as defined in claim 4, in which saidrecesses are arcuate and are located on a common diameter greater thanthe diameter of said bore.

6. A fluid translating device as defined in claim 4, in which saidsurfaces each have a polygonal raised portion with a recess defined ineach leg of said polygonal raised portion.

7. A fluid translating deviceas defined in claim 4, in which saidrecesses extend chordally of the center of said bore.

8. A fluid translating device as definedin claim 4, including thefurther improvement of means for producing line contact between at leasta portion of adjacent surfaces of said opening and said camblock toaccommodate relative movement of said surfaces.

9. A fluid translating device as defined in claim 4, in which saidrecesses are arcuate and have opposite ends located on differentdiameters.

10. A fluid translating device as defined in claim 9, in which saidcamblock has a ring portion defining said opposed surfaces, said ringhaving inner and outer ends, the further improvement of means defininginner and outer notches in said surfaces, respectively, extending fromsaid ends and terminating between adjacent ends of each pair ofrecesses, the inner notches having bases located on a common diameterwith inner edges of one end of each of said recesses and the outernotches having bases located on a common diameter with outer edges ofthe opposite ends of said recesses, whereby the overlapping portions ofsaid plates are exposed to fluid for lubrication during rotation.

11. A fluid translating device comprising a housing having an openingtherein with inlet and outlet ports on opposite sides of said opening; acamblock supported in said opening and having a bore defining a workingchamber; said working chamber communicating with inlet and outlet portsin said housing; a rotor rotatably supported within said working chamberand cooperating with said camblock to define an annular zone, said rotorhaving end plates rotatable therewith and extending in juxtaposedoverlapping relation to opposite ends of said camblock, said camblockhaving a length between said surfaces which is less than the spacingbetween adjacent surfaces of said plate; and means defining line contactbetween the surface of said opening and said camblock, whereby toaccommodate relative movement of said camblock in said opening.

12. A fluid translating device as defined in claim 11, the furtherimprovement of means producing a plurality of spaced recesses in saidend surfaces of said camblock, said recesses being spaced from andcommunicating with said annular zone, whereby fluid in said annular zonewill flow into said recesses and maintain said camblock centered betweensaid plates.

13. A fluid translating device as defined in claim 11, in which saidopening and said camblock are rectangul2 14. A fluid translating deviceas defined in claim 13, in which the opposed sides of said camblock arebeveled from the center toward opposite ends to lar and said linecontact is defined between the side of 5 produce Said lme Contact saidopening having said ports therein.

1. A fluid translating device comprising a housing having a rectangularopening therein; an inner member and an outer member cooperating toproduce an annular space with said members being relatively rotatable,said outer member having a rectangular peripheral surface cooperatingwith said opening, one of said members including portions havingsurfaces in overlapping spaced relation to adjacent surfaces of theother of said members to substantially enclose said annular space; meansdefining circumferentially spaced recesses in the surfaces of one ofsaid members, said recesses being in individual communication with saidannular space, at spaced locations so that pressured fluid in saidannular space will be received in said recesses to maintain said othermember centered between said portions and flow of fluid between saidsurfaces will produce a fluid seal for said annular space; and meansdefining line contact along opposed portions of said peripheral surfaceand said opening, said line contact being centrally spaced and parallelto said surfaces of said outer member.
 2. A fluid translating device asdefined in claim 1, in which said recesses are arcuate and equallyspaced about said annular space.
 3. A fluid translating device asdefined in claim 1, in which said recesses are chordally arranged andequally spaced about said annular space.
 4. A fluid translating deviCecomprising a housing having an opening therein and opposed inlet andoutlet ports communicating with said opening, a camblock supported formovement in said opening and having a bore; a rotor rotatable about afixed axis in said bore and cooperating with said bore to define anannular space; a pair of plates rotatable with said rotor, said plateshaving end portions in overlapping relation with respective opposedsurfaces of said camblock with said camblock having an axial lengthbetween said surfaces which is less than the spacing between said platesto produce limited flow paths from said annular space between said endportions and the adjacent surfaces of said camblock; and means forproducing circumferentially spaced elongated recesses and slots in saidcamblock surfaces, said recesses being spaced from said bore and saidslots placing each of said recesses in communication with said annularspace, whereby fluid translated between said ports will be received insaid recesses and maintain said surfaces spaced from said end portionsand the fluid in said flow paths will seal the annular space from theopening in the housing.
 5. A fluid translating device as defined inclaim 4, in which said recesses are arcuate and are located on a commondiameter greater than the diameter of said bore.
 6. A fluid translatingdevice as defined in claim 4, in which said surfaces each have apolygonal raised portion with a recess defined in each leg of saidpolygonal raised portion.
 7. A fluid translating device as defined inclaim 4, in which said recesses extend chordally of the center of saidbore.
 8. A fluid translating device as defined in claim 4, including thefurther improvement of means for producing line contact between at leasta portion of adjacent surfaces of said opening and said camblock toaccommodate relative movement of said surfaces.
 9. A fluid translatingdevice as defined in claim 4, in which said recesses are arcuate andhave opposite ends located on different diameters.
 10. A fluidtranslating device as defined in claim 9, in which said camblock has aring portion defining said opposed surfaces, said ring having inner andouter ends, the further improvement of means defining inner and outernotches in said surfaces, respectively, extending from said ends andterminating between adjacent ends of each pair of recesses, the innernotches having bases located on a common diameter with inner edges ofone end of each of said recesses and the outer notches having baseslocated on a common diameter with outer edges of the opposite ends ofsaid recesses, whereby the overlapping portions of said plates areexposed to fluid for lubrication during rotation.
 11. A fluidtranslating device comprising a housing having an opening therein withinlet and outlet ports on opposite sides of said opening; a camblocksupported in said opening and having a bore defining a working chamber;said working chamber communicating with inlet and outlet ports in saidhousing; a rotor rotatably supported within said working chamber andcooperating with said camblock to define an annular zone, said rotorhaving end plates rotatable therewith and extending in juxtaposedoverlapping relation to opposite ends of said camblock, said camblockhaving a length between said surfaces which is less than the spacingbetween adjacent surfaces of said plate; and means defining line contactbetween the surface of said opening and said camblock, whereby toaccommodate relative movement of said camblock in said opening.
 12. Afluid translating device as defined in claim 11, the further improvementof means producing a plurality of spaced recesses in said end surfacesof said camblock, said recesses being spaced from and communicating withsaid annular zone, whereby fluid in said annular zone will flow intosaid recesses and maintain said camblock centered between said plates.13. A fluid translating device as defined in claim 11, in which saidopening and said camblock are rectangular and Said line contact isdefined between the side of said opening having said ports therein. 14.A fluid translating device as defined in claim 13, in which the opposedsides of said camblock are beveled from the center toward opposite endsto produce said line contact.